Evaluate the following expression when $d = 9$ and $c = 3$. $5$ $d$ $ + 7$ $c$ $ + 9$
Answer: Substitute $9$ for ${d}$ and $3$ for ${c}$ $ = 5{(9)} + 7{(3)} + 9 $ $ = 45 + 21 + 9 $ $ = 75$